In modern medicine, attempts are generally made to minimize damage to intact tissue. Thus, when circumstances permit, minimally invasive surgery is usually the preferred method of operative intervention used. Small incisions and minimal trauma to the tissue lead to less pain after the operation and to rapid recovery and mobilization of the patient. Laparoscopic surgery, during which complex operations are performed in the abdominal cavity, allows similar results.
Operations of this type, and the instruments required for them, present a particular challenge to the manufacturers of medical instruments since the majority of the operative steps are performed in very restricted spaces and without direct visual contact. Thus, the medical instruments used for these types of operations must not only be able to operate in the smallest spaces but must also function so reliably that visual monitoring is superfluous and unnecessary. The instruments are preferably constructed such that, even without visual contact, the operating surgeon always has feedback which enables him to draw conclusions about the progress of the operation.
This need applies to instruments that are suitable for the separation of tissue. Since scalpels having an open blade are, if anything, unsuitable for minimally invasive surgery (see, e.g., DE 44 44 166 A1), surgeons frequently resort to scissors-type or tong-type instruments having mouth parts. The mouth parts cover the blade during insertion of the instrument as well as hold the tissue to be cut. The blade is then displaced back and forth inside the mouth parts for cutting.
In the tong-like instruments, the blade or scalpel is usually covered completely by the associated mouth parts. It is, therefore, all the more difficult to draw conclusions as to whether the gripped tissue has already been completely separated with one or a plurality of cutting movements. This knowledge, however, is crucial for the positive progress of the operation.
On the other hand, excessively moving the blade when the tissue is already separated can quickly lead to wear on the instrument. It is necessary to check the instruments for their cutting ability and to replace worn blades. This form of maintenance is not only expensive but is also time-consuming. Often it is not possible to replace individual elements of the instruments, leading to the need to replace the entire instrument. Thus, excess wear should be avoided.
The object of the disclosed embodiments is to provide a medical instrument, which allows for reliable separation of tissue while providing long-lasting functionality.